This invention relates to actuators for disk drives that have read/write heads for communicating with a disk cartridge and to head lifting tabs for lifting the heads away from a disk cartridge.
Conventionally, a removable cartridge disk drive has an actuator upon which read/write heads are mounted for communicating with a disk cartridge. Although they may be attached to the actuator in a variety of manners, the read/write heads or "heads" are typically attached to an area of the actuator that is disposed near an end of the actuator. In order to prevent or minimize the likelihood of damage to the read/write heads, they are typically placed in a retracted position within a disk drive until a disk cartridge is inserted into the disk drive. Upon insertion of a disk cartridge, the actuator may be rotated to a loaded position, so that the read/write heads can interface with the disk cartridge, and in particular the storage medium of the disk cartridge. When the inserted disk cartridge is to be ejected from a disk drive, the actuator and the read/write heads are rotated away from the disk cartridge and to the retracted position.
By way of background, actuators are typically of one of two types, either linear or rotary. However, others may be employed. Linear actuators move along a single axis and typically move forward in the disk drive so that the heads can interface with the disk cartridge, and towards the rear of the disk drive to remove the heads from the disk cartridge and into the retracted position. Rotary actuators operate in a similar fashion, but they rotate about an axis, as opposed to moving along a single axis, to engage and disengage the heads respectively with and from a disk cartridge.
Generally, a rotary actuator is attached at one of its longitudinal ends to the disk drive and is not attached to the disk drive at its other longitudinal end. The heads are attached proximal to the unattached longitudinal end of the rotary actuator. In order to support the heads and protect them from damage when a removable disk cartridge is not loaded into the disk drive and when the actuator is not interfacing with the disk cartridge, a load ramp is typically provided in disk drives that employ rotary actuators to support the unattached longitudinal end of the rotary actuator. By supporting the unattached longitudinal end of the actuator, the load ramp holds the actuator in a retracted position and thereby prevents or minimizes the likelihood of damage to the heads.
When the rotary actuator moves the heads to interface with the storage medium of the disk cartridge, the unattached longitudinal end of the actuator moves off of the load ramp and proximal to the storage medium of the disk drive. In this position, the heads can communicate with the storage medium of the disk cartridge. This position of the actuator may be referred to as the loaded position.
In order to support the actuator when it rests on the load ramp, the actuator may have a head lifting tab. The head lifting tab is the part of the actuator that directly interfaces with the load ramp. That is, the head lifting tab slidably engages the load ramp and rests on the load ramp to support the actuator when the heads of the actuator are not interfacing with the storage medium. When the actuator moves so that the heads can interface with the storage medium, the head lifting tab slides along the load ramp until it reaches the end of the load ramp. Upon reaching the end of the load ramp, the lifting tab slides off of the load ramp and the heads of the actuator engage the storage medium. Similarly, when the actuator is moved from the loaded position in which the heads interface with the storage medium, the lifting tab slidably engages the end of the load ramp and slides onto the load ramp and thereby lifts the heads away from the disk cartridge.
The stiffness of the head lifting tab can be significant because as the stiffness of the head lifting tab increases the deflection of the lifting tab is reduced. By reducing the deflection of the head lifting tab, the likelihood of the heads contacting a piece of the disk drive being damaging is reduced. A stiffer head lifting tab also helps increase resonance frequencies in the suspension, thus improving the speed at which the head can be moved on the media to retrieve and write data.
Many prior art head lifting tabs have edges or straight surfaces that engage the load ramp. These edges have the potential disadvantage of gauging or wearing the load ramp after numerous head loading and unloading operations.
The lifting tab configuration must be lightweight to minimize the mass extending from the suspension, yet have sufficient strength such that deflection of the suspension is within a predetermined amount to prevent damage to the lifting tab, heads, or other components.
An aspect of advancing technology has been problematic for disk drive load ramp design and manufacture. As disk drive technology has developed towards lower costs, the size of the slider has been reduced in order to manufacture more sliders per wafer. Therefore smaller sliders reduce costs and the length, width, and thickness of the slider.
Thinner sliders cause a diminished gap (compared with thicker heads) between the suspension arm and the disk surface, which is problematic for the load ramp design and manufacturing. In configurations in which the load ramp extends over top the disk surface, the diminished gap requires load ramps having even thinner ends. This is especially problematic for removable cartridge drives because the disk must be accurately positioned numerous times, and interchangeable cartridges might not have uniform dimensions because of manufacturing tolerances. Producing load ramps that have uniform, knife-like edges by conventional plastic manufacturing is difficult.
Further, the plastic load ramp may wear after repeated loading and unloading cycles. Such wear may cause damage to the disk if the head is not sufficiently lifted. Further, the wear exacerbates the difficulties related to ramp edge thinness.
This invention relates to improved actuators that have improved head lifting tabs for engaging load ramps. This invention also relates to improved disk drives and methods of operating improved disk drives that employ improved actuators that have the improved head lifting tabs.